Forced to build their own prison, striped-suited laborers lay the foundation and construct the walls of Auschwitz. Located near the Polish town of Oswiecim, the swampy site had housed an army barracks during World War I. At Heinrich Himmler's order, SS-Hauptsturmführer Rudolf Höss inspected the area in April 1940 and proclaimed it ideal for incarcerating the rapidly growing number of prisoners, mostly Poles.Photo: National Museum of Auschwitz-Birkenau / United States Holocaust Memorial Museum Photo Archive

The headquarters of the Nazis' "euthanasia program" was located in this benign building at Tiergartenstrasse4 in Berlin. The T-4 division was created on Hitler's orders and headed by Philip Bouhler and Viktor Brack. The organization was responsible for administering "mercy" killings to the mentally and physically handicapped. Planning began in the spring of 1939, and the first murders occurred in October. Eventually, 70,000 people were murdered under the auspices of the T-4 program.Photo: Landesbildstelle Berlin / United States Holocaust Memorial Museum Photo Archive

This chart details the prisoner markings used in German concentration camps. Badges identify the following categories of prisoners: political, professional criminal, emigrant, Jehovah's Witness, homosexual, German shy of work, and others. The hierarchical ordering of prisoners sentenced to concentration camps created a Byzantine world of power relations.Photo: KZ Gedenkstätte Dachau / United States Holocaust Memorial Museum Photo Archive

1940: Six "euthanasia" centers are set up in Germany to murder Jews, the mentally ill, the elderly, the physically ill, and the handicapped.

1940: President Franklin Roosevelt puts the question of Jewish immigration into the United States into the antisemitic hands of Assistant Secretary of State Breckinridge Long and associates in the State Department. A political ally of the president, Long opposes "excessive humanitarianism" in regards to the Jews. Tainted by a general xenophobia and a predilection for Mussolini and Italian fascism (Long was ambassador to Italy), Long seems particularly distressed at the prospect of more Jews entering the United States.